I have a 1985 LB9 that is getting worn and I want to build up another engine for replacement before it is absolutely needed but I want to be able to bolt up most of my existing components to save some dough during the swap out, i.e. TPI system, etc... I know the engine in the car now is a 1985 305 but the VIN codes lists an LB9. What does the LB9 stand for and is there a recommended small block easier to rebuild?

 

It doesn't stand for anything... it's not an acronym. It's just the GM RPO for the 305 Tuned Port engine.

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91 Trans Am WS6
Bright White
5.0 TPI auto
Flowmaster 3" 2 chamber catback
Trans Go shiftkit
2000 stall converter

Built on Wednesday

 

I agree with MrJ's response. 'LB9' may be interpreted internally by GM such that each character has significance, but as far as the general public knows, and probably everyone else (except maybe the engineers) at GM , 'LB9' means 305ci TPI. The easiest to rebuild, few would argue, is a 350. The Motor Swap board has some good info on this.

 

L means engine, as every GM engine starts with L, as in L98, L03, LT1, LS1, LS6, LB9, etc. The B and the 9 I have no idea. LB9 means a 305 TPI engine, like was said above.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

thanks all, wasn't sure if it was some off model GM put out or what... i've been reading the message board on motor swap to the 350 but i would really like to stay with the economy of the 305 or does it really make a difference between a 305 to 350? i get pretty good gas mileage right now and still have a little power to play with when i want it... also don't know if i can put a 350 with 5spd in a T-Top model TA, any thoughts?

 

I thought the LB9 was a 350. Anyways, yes you can put a 350 in with t-tops (They produced a 350 with t-tops). If you get a crazy engine (350hp +) I would recommend getting sub frame connectors (I would get them even if you dont put a crazy engine in), they will stiffen up the frame!! I would also get a strut brace.

 

Actually, there doesn't seem to be a great difference between the 305 and 350 for gas mileage (auto for auto being the most comparable). The gears tend to be the greatest contributor of any difference.

On the highway, I get 24-25 mpg. And that is before I started to optimize my eprom and I haven't even invoke the "Highway Mode" in my eprom yet (though I have tested it to see if it worked).

Some of the guys with the 305 and 2.73 gears have said they get up to 27 mpg. Those that have gears similar to my 3.23s say they get basically the same gas mileage.

 

The L98 is the 350 TPI engine, and I second the t-tops and strut tower brace recommendations.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

ZZ4 doesn't start with L

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86 IROC 305 TPI LB9 700R4 W/ Shift kit, K & N, Flowmaster gutted cat 95 Z tips, airfoil, 160 thermo, removed emissions, Summit cam kit 442 lift springs and lifters, ADS super chip, Summit timing chain, modified MAFS, tranny cooler, polished rims, Good Year yellow letter nascar 235/55 tires, polished runners and plenum, 145 Speedo, remote start, keyless entry, alarm, yellow neons underneath.

 

ZZ4 also isnt a standard engine in a GM car. Its a specialty crate engine. I meant engines that come from the factory in GM cars and trucks.